Login to Access Video or Poster Abstract: MP67-14
Sources of Funding: Funded in part by the Sidney Kimmel Center for Prostate and Urologic Cancers and the National Cancer Institute Training Grant T32 CA082088 (MG)

Introduction

Prior case reports and observational studies have shown that patients with gastrointestinal stromal tumors (GISTs), a subtype of soft tissue sarcomas (STSs), are at increased risk of other malignancies, including renal cell carcinoma (RCC). The association between RCC and other subtypes of STSs has not been studied; thus, we aim to assess this relationship and report our experience on patients with RCC and GISTs.

Methods

We retrospectively reviewed our institutional database to identify patients with pathologically confirmed STSs and co-occurring RCC between January 1980 and June 2016. Clinical and pathologic characteristics of patients with RCC and STS subtypes were collected. Chi square analysis and Fisher’s exact test were used to compare RCC in GIST to other STSs.

Results

We identified 5371 patients with STSs and 402 with GISTs. Mean follow-up time was 11.4 [3.6–23.6] years. RCC had a statistically significant (p=0.009) higher co-occurrence in GIST (n=6, 1.6%) compared to other STSs (n=20, 0.40%). The GIST cohort compared with the other STS cohort had a higher proportion of metachronous occurrence (66.7% vs. 40%). In addition, when analyzing the pathologic characteristics of GISTs compared with other STSs, a higher proportion of papillary carcinoma was noted in the GIST cohort (33.3% vs. 10%). The prevalence of RCC differentiated by STS subtype was observed to be: GIST (n=6, 23%), liposarcoma (n=6, 23%), leiomyosarcoma (n=4, 15%), fibrosarcoma (n=3, 12%), and other (n=7, 27%). Clinical and pathologic characteristics of the GIST and other STS cohorts are shown in Table 1.

Conclusions

Diagnosis of RCC in patients with GISTs is significantly higher than those with other STS subtypes. Additionally, a higher proportion of papillary carcinoma compared with other histologies in RCC is observed in patients with GISTs, which is consistent with other reports in the literature. While the incidence of RCC in our GIST cohort is similar to the reported incidence in the general population, the differences in incidence and pathologic characteristics compared to other STSs warrant further investigation into clinical and genetic associations of GISTs and RCC.

Funding

Funded in part by the Sidney Kimmel Center for Prostate and Urologic Cancers and the National Cancer Institute Training Grant T32 CA082088 (MG)